An examination of structural features and relationships in Balansia subgenus Dothichloë

Abstract

Balansia subgenus Dothichloë is defined to include only species of graminicolous Clavicipitaceae that are endophytic, form stromata on leaves or culms, and produce nonstipitate black ascomata. Species included in subgenus Dothichloë are Balansia aristidae, B. epichloë, B. henningsiana, B. nigricans, B. strangulans, and Balansiopsis gaduae. The genus Balansiopsis is invalidated since its type B. gaduae is herein classified in subgenus Dothichloë. Balansia subnodosa is considered to be a synonym of B. gaduae based on morphological and anatomical similarities of the ascomata. Phylogenetic relationships in Dothichloë are evaluated through examination of ribosomal DNA ITS (internal transcribed spacer) sequence data. It is concluded that at least two subclades are evident in the subgenus, including the B. gaduae/B. nigricans subclade and the B. aristidae/B. henningsiana/B. strangulans subclade. Sequence divergence of B. epichloë makes it difficult to confidently assign it to either subclade. A dichotomous key to Dothichloë is included along with descriptions of B. aristidae, B. epichloë, B. gaduae, and B. henningsiana.

Key Words:

• Ascomycotina
• Balansiopsis
• Clavicipitaceae
• endophytes
• grasses
• molecular systematics